Train control



Patented Aug. 21, 1928.

UNITED STATES PATENT OFFICE.

HALTER W. W'ENHOLZ, OF ROCHESTER. NEW YORK, ASSIGNOR TO GENERAL RAIL-WAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

TRAIN CONTROL.

I Application filed. November 20, 1924. Serial No. 751,061.

This invention relates to automatic train control Systems, and moreparticularly to the trackway equipment of a train controlsystem of thewell known continuous inductive t pe. Y

In block signal systems, it is sometimes necessary to divide a block,that is, that portion of track on any part of which the pres ence of atrain produces the same controlling effect on the block signals, intotwo separate isolated track circuit sections. For example, in the typeof block signaling system for single track railroads, commonly known asthe absolute-permissivc-block system, one form of which is disclosed inthe patent to YVight, No. 1,294,736, dated Feb. 18, 1919, it isnecessary to have the block between opposing signals, particularlyadjacent to the sidings, divided into two separate track cir cuitsections, each having a track relay, in

'order that the track relays may be operated sequentially during thepassage of trains in opposite directions. .Also, on double trackrailroads, on account of the length of the block, ballast conditions, orother practical considerations, it is sometimes necessary to divide theblock into two separate track circuit sections.

In applying continuous inductive train control to such divided blocks orcut-sections, it is desirable to supply the train control circuitthroughout the length of the block and control it from one point. Inother words, it is desirable to make the track rails of the blockcontinuous with respectto the alternating train control current, whileseparate or isolated tor-the direct current of the track circuits sothat either the track phase or" a continuous inductive control system,or both the track phase and line phase of such system may be suppliedthroughout the length of the block and conveniently controlled at onepoint.

The principal object of the present invention is to provide anarrangement of devices and circuits which will enable the train controlcurrent to be supplied throughout the length of the block. while thedirect track circuit current is confined to the separate track circuitsections of the block.

In describing the invention in detail ref erence will be made to theaccompanying drawings in which Fig. 1 shows conventionally a block of anautomatic block signal system composed of two sections divided byinsulating joints, hav mg train control apparatus superimposed thereonembodying the present invention; and

Fig. 2 shows a junction point of the two sections of a block in asimilar system in which only one of the rails is insulated, and having amodified form of train control apparatus associated therewith.

Referring to'Fig. 1, to simplify and facilitate the explanation of thenature of the in- Vention, there has been illustrated an embodimcntofthe invention applied to a block of a double track railroad which isdivided into two separate direct current track circuit sections. Forsimplicity, Fig. 1 merely shows provision for supplying a track phase,track circuit, or loop circuit current "for the train control system,that is, alternating current flowing down one track rail and back theother at any given instant; but it should be understood that the usualtype of 3-position continuous inductive type of system, employingtheline phase current as well as a track phase current, may be used inconnection with the invention. The car apparatus of the train controlsystem, which may take any one of the well known or has not been shown.

In Fig. 1 there has been illustrated a block I, with the adjacent endsof two other blocks H and J. For simplicity, it is assumed that allblocks will be equipped the same, so that a description of one willsuffice for all; and for convenience, the same reference characters withdistinctive exponents are used for corresponding parts and circuitsassociated with the differentblocks. Using the reference characters forthe block I, the usual track rails 1 are provided with insulated joints2 defining the ends of this block, traflic being from left to right, asindicated by the arrow.

The block I is divided into two track circuit sections I and I by a pairof insulated oints 3. Atthe entrance end of the first or rear section Iis a track relay 4 connected across the track rails in the usual manner.The track relay 5 for the second or forward section I is connectedacross the track rails at the exit end thereof. At the exit end of thefirst section I is a track battery 6 which is connected by wires 7 and 9and an inductive reactance or impedance 8 across the track railssuitable forms at the exit end of this section; and a track battery 10is connected across the track rails at the entrance end of the secondsection I by wires 11and 12 and said inductive reactance 8 in asimilarmanner. I ance or impedance"'8has"'aresistance cone sponding to theusual limiting resistance con;

' trackrails 1, in series with a resistance or impedance 15;. Thisresistance, together with the' internal resistance of the Secondary, ismade high enough so as not to shunt out the direct track circuit currentfrom the track relayf), or interfere with the proper operation ofthistrack relay. This resistance 15, is

ordinarily made largely, if notwholly, noninductive, but may have asmuch inductive reactance asmay. be required under someconditions' toobtainphase displacement. The primary of the transformer is energizedfrom the usual transmission line 16 and has itscircuit opened and closedin accordance with traflic conditions in the next block in advance. Inthe arrangement shown, the circuit of the primary of this transformer,includes the frpnt contact of a line relay HR which has an energizingcircuit passing through the front contacts ofth'e-two track relays ofthe next block in advance. This line relay also serves to control theindication 0f the Wayside block signal Z, which may be of the semaphoretype, as shown, orof any other suitable type, together'with suitableprovisions for obtaining the three indications of stop, caution andproceed; approach lighting, if color light signals are used; and otherexp'edients, all, in accordance with the knowledge and teachings of thear t It will be evidentthat the direct track circuit current is confinedto each track circuit section, excepting. 1 leakage through the ground.The track batteries are preferably connectedto oppose each other,asshown, this serving to reduce the potentials to ground and alsothe'direct current voltage in the conductingpath' through which thealternating train control current flows. Train control current-flowsthrough t-he length of the block in the following circuit":-Beginnin'gatthe secondaryof transformer 14, impedance 15, rail 1, Wires 12 and 7,battery 6,1ail 1, track relay & (orthe wheels and axles of a train),

The inductive ractrail1,wires9and 11, battery 10, raill back to thesecondary of transformer 14. This current is cut off the block if thenext block in advance is occupied, thereby producing the caution or stopindication in the 2-position type ofcontinuous"inductive system. A trainin the first or rear section deprives the following 'tra'iifin thatsection of train control current by-the shunting action of its wheelsand axles; and similarl y, a rennin the second or forward sectionsshunts out the train control current from the first or rear section. Atrain entering an occupied blockdoes not receive train control currenteven though that current is supplied to the track rails of thatbloc-kbecause the nextblock in advanceis not occupied. p

Fig.2 shows a'modified arrangement, using one insulated joint 3? betweenthe track circuit sections of the block. The trac lr batteries 6;"? and10? areco'nn ected wires ll and Winseries' around this joint inopposition; and the impedance 8 isconnectedfrom the other rail to thewires between the'jbatteri'esi as shown. It willbe evident that theinsulated joint 3? isolates the two track sections so far as the directtrack circuit current is concerned but the alternating current flowsdown one rail without opposition and, down the other rail'around thejoint 3"- through the two batteries '6 and 10 and wires'll and 7 inseries. f

Havin thus shown and described in a rather spceitic'manner two ratherspecific embodimentsofthe present invention, it is desired tobeiinderstood th 'at the particular arrangements illustrated hav'e beenselected so as to facilitat'eth'e description of the invention ratherthan to show the scope'th'ereof, and that various changes, modificationsand additions maybem'ade'to adapt the'invention to single traclrsignaling systems, such as the well known absolute perinissive blocksystein'. isolated ,traclr sections for crossing signals,"or the like,without departing from the scope of the invention or the idea ofin'eai'is underlying the same. 7

What it is desiredto secure by Letters Pat ent. ofthe United Statesis:--

1, Trackway apparatus for atrain control system employing direct currentand alternating current comprising, an insulated section of'thetrackrails, means for independently impressing a direct ciirre'nt potentialacross twoportions of'said section of the track'rails, and forimpressing alternating currentpotential across the entire section of thetrack rails;

2; Infanautomatictrain control system; in combination trackw'ayapparatus for wayside signal andtraincontrol purposes comprising; asection oftrack rails divided into two portions by insulating joints;means for impressing an alternating current potential for train controlpurposes acrossone end of ilii:

' control current through the entire length of said section and forindependently impress-' ing direct currentpotentials for wayside signalcontrol purposes across the said two insulated portions of said section.

8. Trackway apparatus for automatic train control systems comprising, asection of the track rails divided into two portions by insulatingjoints, partial circuits each in cludin a source of energy connectedacross the track rails on each side of said insulating joints, aninductive reactance common to said partial circuits, whereby currentfrom said sources of energy may flow independently in said two portionsof the track rails and a distinctive alternating current may flow in therails of the entire section.

'4. 'lrackway apparatus for automatic train control systems comprising;a section of trackway divided into two portions by insulating joints; atrack wayside signal controlling circuit for one of said portionsincludin a track relay, the two track rails of said portion, a trackbattery and a reactance coil in series; a track circuit for wayside signal control purposes for the other of said portions including a secondtrack relay, the two track rails of said other portion, a second trackbattery and said reactance coil in series; and a track circuit for traincontrol purposes including the track rails of the entire section and thetrack batteries of the said two portions in series.

5. Trackway apparatus for automatic train control s* stems com risin twosuc cessive direct current trackcireuits for wayside signal controlpurposes each comprising insulated portions of the two track railsconnected in series through a common portion including a reactancecoil,and an alternating currenttrack circuit for train control purposessuperimposed on said direct current track circuits including the trackrails of said two direct. current track circuits, said reactance coilpreventing the flow of alternating current from one rail to the other atthe junction of said two direct current track circuits.

current, and means permitting the flow of current from said distinctivesource down one rail of said two sections and back through the other andpreventing the How of current from one rail to the other at the unctionof said sections.

T. 'lracliway apparatus for auti'imatic train control systemsecniprisin' a track sect tion, a relay at each end of said track bridgedacross the rails at one end of said track section, and means includinganother source of current and a device permitting the flow oi currentfrom said another source but not permitting the ready flow of current ofsaid particular character connected in series and bridged across therails at an in termediate point.

8. 'l 'raclzway apparatus for automatic train control systemscomprising, a track section, a relay at each end of said track section,a source of current for each of said relays bridged across the rails atan intermediate point in said section, another source of currentdistinctive in character bridged across the rails at one end of saidsection, and means for preventing current from said another source fromflowing from one rail to the other at said intermediate point.

9. Tracliway apparatus for automatic train control systems, comprising,a section of track divided from the restof the trackway by insulatingjoints, a source of alternating current bridged across the rails at oneend of said section, a battery having an inductive reactance in seriestherewith connected across the rails or" said section at an intermediatepoint, whereby due to the impedance of said inductive reactance to theflow of alternating current the source of al ternating current is notshunted by said bat tery and the alternating current potential isapplied across the rails throughout the entire section.

10. Traclrway apparatus for automatic train control systems, comprising,a track portion divided by insulating joints into two sections, a. trackrelay for each end of said track portion, a source of energy bridgedacross the rails of each of said sections adjacent said insulatingjoints, another and distinctive source of energy of a diiferent kindbridged across one end of said track portion and having in seriestherewith a device for limiting the flow oi current of the kind derivedfrom the first mentioned source of current, and means interconnectingthe two rails and permitting the flow of current from said distinctivesource down one rail of said two sections and back through the other andpreventing the ilow of current from one rail to the other at thejunction of said sections.

11. Trackway apparatus for train control systems, comprising, a stretchof track divided by insulating joints into two in sulated sections,means bridging each insula ing joint and including a track battery, aninductance connected between the two section, a source of current of aparticular character 1 bridging means, and a source of alternatingcurrent connected to the rails at one end; of said stretch of track. V

12. Trackway apparatus for-train control systems, comprising; a stretchof track divided by insulating, joints into two insulated sect-ions,means bridging each insulatingjoint and including a track battery, aninductance connected betweenthe two bridg- 'ing means, said trackbatteries being connecte'd V in.-- opposition to I each other throughthe nduotance a-source of alternating current connected; across the121118 atone endcfi said; stretch ofitrack a current limiting re- WALTER1V .VENHOLZ.

